For centuries, explorers have searched for the Bible's most sacred religious artefacts. One of the most mysterious of these objects is the famed Ark of the Covenant. The gold-plated wooden chest - one of the most instrumental symbols of faith and God's presence - was believed to house the two tablets bearing the Ten Commandments. The Ark's exact whereabouts has long puzzled scholars. Where did it go? And why has it remained such a mystery?